The test Testing was a simulation of an electrical power outage to aid Assistance the development of a safety procedure for maintaining cooling water circulation until the back-up generators could provide Supply power .

On Oahu , a power outage was reported Reporting , affecting Influence 2,400 customers .

The blackout Motion on 31 July is the largest power outage Motion in history .

The outage Motion affected Influence more than 620 million people , about 9 % of the world population , or half of India 's population , spread across 22 states in Northern , Eastern , and Northeast India .

The 30 July 2012 blackout Motion affected Influence over 400 million people and was briefly the largest power outage in history by number of people affected Influence , beating the January 2001 blackout Motion in Northern India ( 230 million affected ) .

They were reportedly caused Causation by `` a temporary system balance at 1:29 a.m. due to a sudden plant outage . ''

Widespread power outage and property damage ensued Coming_to_be due to the storm 's strong winds .